99Eternal

I just took some measurements for the hell of it, 12.5v at the terminal with the car off.

I am unable to get a signal from the RCA's. I am measuring ac voltage between the tip of the rca and the outside metal shield. It hits 0.1VAC for a split second but that's about it. The head-unit is supposed to be 2.5v preouts.

I've never measured RCA signal before so is there something I am doing incorrectly? Do I need to have the volume at max? (it was only set low). I'm thinking since the voltage would remain fixed the current rises with more volume to make up the extra wattage, so the volume shouldn't matter.

So should I not have 2.0-2.5v at the amp RCA's after a 17ft rca run?
Could this be the reason why I am having to max my gains?

unknown123

try measuring it with DC voltage, also, check the resistance of the RCAs

Dukk

Nope. Audio signals are AC.

Nope, as you increase the volume the voltage goes up. Set it to max, play pink noise, measure it on AC voltage, and see what you get. I'm curious why would you think voltage would stay constant and the current increase with volume?

unknown123

[QUOTE=Dukk;657888]Nope. Audio signals are AC.


Lol, sorry i read it somewhere that its dc... wrong info, but im still learning, Sorry for the wrong advice

masterelyt

With any subs I've had, they sound much louder when they are facing the back of the vehicle.... I've also noticed that if there's something between the subs and the listening position (driver's seat), like if the subs are behind the back seats in an SUV, they will sound louder and hit with more impact than merely being right behind your head on the back seat.

Bass sounds louder the more stuff it bounces off of :P

Dukk

It has more to do with reflection and cancellation.

Move the box to the trunk, face it backwards, and see how that works.

8v-of-fury

what size wiring are you using? Did you upgrade your wiring when you went to an amp 3x as powerful?

99Eternal

4AWG - went with that size from the start in case I wanted to upgrade.

I beleive I have found my issue, though. When measuring the resistance of the voice coils on the sub, the reading fluctuates from 2-16 ohms, which from what I understand is a clear indication that the sub is damaged.

I could certainly see one of the voice coils being damaged acting as a blockade to current.

I have 2 JL 10w3's in a JL H.O. Enclosure designed specifically for 2 10w3's on the way. Picked all that up brand new for $420 shipped. Hopefully have them by next weekend.

Keeping my finger's crossed that this was in fact the issue. I discontinued using my old sub to avoid damaging my amp and vehciles electrical system.

Thanks everyone for your input, I will let you know if the sub being damaged was in fact the issue when the new subs come in.

99Eternal

Are you talking about the RCA voltage or the power wire voltage?

For the RCA's since they are signal not power, you are correct the voltage would change with volume.

The reason why I think the power wire voltage remains constant is because your battery/alternator voltage remain constant. 12v from the battery and 2.4 from the alternator. If this value were to fluctuate, you would never know what wire type is required, because your current would also rise and fall to compensate for the change in voltage. If your voltage drops, your current goes up in. A healthy electrical system maintains voltage...(unless you have a massive system which would cause voltage drop on hits)


Anyways, I think my issue is one of the voice coils on the sub is damaged. The impedance fluctuates from 2-16 ohms. New subs on the way will let you guys know.

99Eternal

Thanks guys, I will give that a try with the new subs.

Just FYI, I think I have found the problem. When measuring the resistance of the voice coils, the reading fluctuates from 2-16ohms. I read that this is a pretty clear indication that the sub is damaged, and I could certainly see a fluctuating impedance causing what seems like a power issue and definitely would cause a performance issue.

Thanks!